Sound reproducer



IVI. J. TRUIVIBLE.

SOUND REPRODUCER.

APPLICATION FILI-:D APR, 25. I92I.

Patnted; Oct. i7, 1922..

revisarse oei., i7, iaaa UNHTE @Filial-@ido 'MILN 5'. TRUMBLE, OFTALHAHIBEJA, CALIFORNCA.

sonno anraonocna.

A.hmplileaftion nled'flprll ay 19531.

To all whom it may concern:

Be it known that l,

MILON J TRUMeLn,

a citizen of the United States., residing at Alhambra, county of LosAngeles and State 5 of California, have invented a new and use- Jfulimprovement in Sound Reproducers, of which the following is aspecification.

of soundand is invention relates particularly applicable to to thereproduction the reproduction of sound from phonograph records.

Referring to the drawing which is for illustrative purposes only,

Fig. 1 is a side elevation of my invention when applied to a soundrecord is groove.

Fig. hy the line 2-2 of disc record in which the formed on the side'oithe 2 is a section on a plane represented Fig. 1, and,

, Fig. 3 is a section on a plane represented by the line 3-3 ln the formof et Fig. 1.

the invention shown., a

supporting structure 11 isprovided in which a sound ch amber 12 isformed., the front of this sound chamber being closed by a maindiaphragm 13 and the bach of this sound chamber having an openinglllthrough which the sound p llflounted on pivots E cn i hy means ciscrews 21 is a stylus holder 22 asses into a tone arm 15. 'the structure11 which has a socket in which the stylus or needle 23 may loe placed,this needle being clamped therein by means of a screw 24C. rlhe stylusholder 22 extends up and is provided with a round end 25 having a facingof rubber or similar material which presses against the center oi thediaphragm 13. 'Eiztending through an opening in the stylus holder 22 isone end of a cross lever 31, this cross lever being in ounted on pivots32 which' are parallel to the stylus holder 22. 7llhe other end 38 ofscrew 34., the roun against a drum diaphragm the iront ot an auxiliarychamber 36, such chamber having a hack thereof.

it will 'be noted that the is substantially at holder 2Q which ismovements parallel to the diaphragm 13 and the stylus holder 22. By

at right angles to the cross lever 31 carries a ded end or which presses35 which closes relief opening 37 in the cross vvlever 31 right anglestothe stylus thus restrained from any Serial No. tslwt restraining thestylus holder in this manner, l eliminate a great deal oi? the scratchysound produced hy ordinary reproducers. IThe screw 34 is set up untilthe drum diaphragm 35 exerts considerable pressure between the end 25 ofthe stylus holder 22 and the main diaphragm 18. l have found that thedia'- phragm 13 may be conveniently made oit mica and that the drumdiaphragm 35 may be conveniently made of very thin metal. l have alsofound that it is preferable to malte the drum diaphragm 35 and the maindiaphragm 13 of different diameters so that they wil have differentperiods of vibration. The reproduced sound is improved by placing ananvil in the sound chamber 12' and l pre` ier to use a conical shapedanvil i6 suspended in such chamber at three points by means oit screws4:7. The anvil i6 is provided with an opening i8 extending therethroughat right angles to the diaphragm 13, the ace of the anvil having aseries of circular grooves and the sides of the anvil'being spaced apartand substantially conforming to the walls of the chamberil.

ll have ,further found that by making a reproducer substantially asshown, that y. l produce a very clear reproduction o the record whichreproduction is not marredhy scratching noises which are oftennoticeable when an ordinary'reproducer is used.

l claim as my invention:

1. a phonograph reproducer, the comhination of: a 'supporting structure;a mainv diaphragm closing the h'ont oi a sound cham loer formed in saidstructure; means for attaching a tone arin to said structure; a styhisholder flexibly mounted on said structure and having its upper end incontact with said diaphragm; means for securing needle in the other endoit said stylus holder; a cross lever engaging said stylus holder; drumdiaphragm against which one end of said cross lever rests; .and pivotsparallel to said stylus holder v upon which said cross lever isAsupported. l

2. ln a phonograph reproducer, the coinbinationvof: a supportingstructure; a main diaphragm closing the front ci a sound chamher formedin said structure; means tor attachin a tone arm to said structure; .astylus ho der dexibly mounted on said strucmamas@ upon which`xsmicfcross lever f, I have hereunto set, 10 goles, California, this21.

dmphm against which one ond of' said cross lover rests; amd piyotsparallel to said.

oN mmm.,

